(a) Field of the Invention
The present invention relates to a light source for a display device.
(b) Description of the Related Art
Image display devices, such as a television receiver or a computer monitor, are classified as either a self-luminescence display device capable of self-emitting light or a light receiving display device requiring a separate light source. Organic light emitting displays (OLEDs), vacuum fluorescent displays (VFDs), field emission displays (FEDs), plasma display panels (PDPs), etc. are examples of self-luminescence display devices, while liquid crystal display (LCD) devices, are an example of the light receiving display device.
Generally, LCD devices include a pair of panels having field generating electrodes disposed at an inner surface, and a liquid crystal layer interposed between the pair of panels having dielectric anisotropy. In an LCD device, a variation of a voltage difference between the field generating electrodes, i.e., a variation in a strength of an electric field generated by the field generating electrodes, changes a transmittance of light passing through the LCD device. Thus desired images are obtained by controlling the voltage difference between the field generating electrodes.
In the LCD devices, light may be provided by a natural light source or an artificial light source separately employed in an LCD device.
A backlight device is a representative artificial light source for the LCD devices. The backlight device utilizes light emitting diodes (LEDs) or fluorescent lamps such as cold cathode fluorescent lamps (CCFLs) and external electrode fluorescent lamps (EEFLs), etc. as the light source.
LEDs have eco-friendly characteristics since the LEDs do not use mercury (Hg) and a working lifetime of an LED is longer than a working lifetime of most other light sources due to stable characteristics of the LED. For these reasons, the LED is a popular choice as a next-generation light source.